In a wireless communication system, a transmitter may utilize multiple (T) transmit antennas for data transmission to a receiver equipped with multiple (R) receive antennas. The multiple transmit and receive antennas form a multiple-input multiple-output (MIMO) channel that may be used to increase throughput and/or improve reliability. For example, the transmitter may send up to T data streams simultaneously from the T transmit antennas to improve throughput. Alternatively, the transmitter may send a single data stream from all T transmit antennas to improve reception by the receiver.
Good performance (e.g., high throughput) may be achieved by transmitting one or more data streams with beamforming. To perform beamforming, the transmitter may obtain a channel estimate for the MIMO channel, derive steering matrices based on the channel estimate, and perform transmit spatial processing with the steering matrices. The transmitter may obtain the channel estimate in several manners depending on the duplexing scheme used by the system and the capabilities of the transmitter and receiver. It is desirable to support beamforming with as low complexity as possible for both the transmitter and receiver.